1. Field of the Invention
The present invention relates to a transmission device, a transmission method, and a program, and more particularly to a transmission device, a transmission method, and a program capable of adding an error correction code (ECC) to data such as, for example, a video signal for transmission, without generation of redundant data.
2. Description of the Related Art
A transmission device such as a portable telephone or a notebook type personal computer (hereinafter, referred to as a notebook PC) uses a movable member in a hinge portion which makes a connection between a main body portion which is operated by a user and a display portion which displays information, for the most part. However, a plurality of signal lines or power supply lines is disposed in this hinge portion. For example, wires for video signals transmitted to the display portion, or an LED (light emitting diode) backlight for providing light to an LCD (liquid crystal display) are disposed in the hinge portion. For this reason, in order to maintain the reliability of the signal lines or the power supply lines, it is necessary to reduce the number of the signal lines passing through the hinge portion.
Hitherto, in many transmission devices, data is transmitted between the main body portion and the display portion in a parallel transmission method in which plural pieces of data are transmitted using a plurality of signal lines, and thus the number of signal lines used for the data transmission increases.
Therefore, in order to reduce the number of the signal lines used for the data transmission, the parallel transmission method may be changed to a serial transmission method.
Here, the serial transmission method is a method in which a plurality of data streams input in parallel is converted into a serial data stream (hereinafter, referred to as serial data), and the serial data obtained by the conversion is transmitted using a single signal line. However, in the case of the serial transmission method, in order to realize a transmission rate similar to that in the parallel transmission method, it is necessary to perform the transmission with frequency clocks higher than in the parallel transmission method.
If the clocks come to have a high rate in a serial transmission path, a frequency spectrum of the transmission signal becomes broad in the band and thus an electromagnetic interference (EMI) occurs in some cases. The high rate of the clocks leads to increase in power consumption. On the other hand, in recent years, there is a demand for data transmission at a higher rate due to great improvement in the resolution of LCDs.
For this reason, a study on the suppression of an effect of EMI, the decrease in an amount of power consumption, and the realization of the high rate data transmission, is necessary. As one method satisfying the demand, serial data is encoded based on an appropriate encoding method.
As well known encoding methods, there are, for example, NRZ (non-return to zero) encoding method, a Manchester encoding method, an AMI (alternate mark inversion) encoding method, and the like. Also, Japanese Unexamined Patent Application Publications No. 3-109843 discloses a technique in which data is transmitted using the AMI encoding.
Further, recently, an encoding method (hereinafter, referred to as a new method) has been developed in which a DC component is not included, and a clock component is easily extracted from a received signal. This new method is a method in which serial data is encoded by the AMI encoding method, the Manchester encoding method or the like, and clocks are synchronously added to symbol streams obtained by the encoding so as to be transmitted. A transmission signal generated based on the new method does not include a DC component and thus can be transmitted via a power supply line. In addition, it is possible to extract a clock component from the received signal without use of a PLL (phase locked loop) circuit. Thereby, if the new method is applied, it is possible to reduce the number of signal lines and power consumption.